As disclosed in, e.g., Patent Document 1, air purification devices configured to purify air by discharge have been conventionally known. The air purification device includes a discharge device with a pair of a discharge electrode and a counter electrode. In the discharge device, voltage is applied between the pair of electrodes to generate streamer discharge. In generating streamer discharge, high-reactive active species such as ozone and radicals are generated, and harmful components and odorous components contained in air are decomposed by the active species.